Relationship between the Salt Accumulation and the Drought Resistance in Several Woody Plants in Arid Zone | 干旱区木本植物盐分积累与其耐旱性的关系

chinois. 通过对干旱区4种木本植物体内Na＋,K＋浓度和水分、光合等指标的测定、比较,分析盐分积累与其耐旱性的关系。结果表明：梭梭和柽柳能够吸收、积累较多的Na＋,而花棒和沙枣组织Na＋浓度相对较低;与花棒和沙枣相比,梭梭和柽柳具有较低的组织水势和渗透势、较小的蒸腾失水量和较大光合作用有效水势范围。表现为植株水势、渗透势和蒸腾失水量与其组织Na＋浓度呈负相关,而光合作用有效水势范围大小则与其呈显著正相关。由此可见：盐分积累能够降低组织渗透势和水势、增强水分吸收的动力,同时还可以减少蒸腾耗水,有利于植株在低水势下维持较高的光合作用能力,即干旱地区的植物通过积盐可以增强其抗旱能力。

anglais. The plants in arid zones tend to accumulate more salt because the evaporation is much higher than the rainfall in arid environment, and because the selective uptake of water by plant roots results in the rise of salt concentration in solutions in the rhizosphere. In this study, parameters such as the Na ＋ and K ＋ concentrations, as well as the water status and photosynthesis were measured and analyzed. The results showed that H. ammodendron and T. ramosissima were able to absorb and accumulate more Na＋ than H. scoparium and E. angustifolia. In accordance, H. scoparium and T. ramosissima also had lower water potentials and osmotic potentials in their tissues, as well as lower transpiration and larger range of water potential for effective photosynthesis than H. scoparium and E. angustifolia. There was a negative correlation between the Na ＋ concentration and the water/osmotic potentials of the plants, a negative correlation between the Na ＋ concentration and the transpirational water loss; but a positive correlation between the Na ＋ concentration and the range of water potential for effective photosynthesis. It is therefore concluded that the salt accumulation could decrease the osmotic potential and water potential of plant tissues, enhance the driving force of water absorption, and reduce the transpiration of the plants, which was beneficial for the plants to retain a relatively higher photosynthesis, implying that salt accumulation in plants could enhance the drought resistance of the plant species in arid zone.